I. Field of the Invention
This invention relates to door latches and, in particular, to a door latch having an adjustable backset to accommodate a specific door configuration.
II. Description Of The Prior Art
Typically, doors are provided with a standard backset which defines the distance between the rotational axis of the operating knob and the edge of the door from which the latch bolt extends. Most modern doors are provided with a backset of 23/8" while older doors and a minority of modern doors have a backset of 23/4". Thus, if the door hardware needs to be replaced, the user must locate a door latch which has the identical backset. Accordingly, hardware suppliers must stock latches for both types of backsets.
Adjustable backset door latches have been developed which utilize various mechanisms to vary the distance between the door edge and the rotational axis of the latch knob. However, the available space within the door is limited and therefore the length of the latch must correspond to the door configuration. Several prior known latches with adjustable backsets employ telescopingly extendable mechanisms which required additional preparation of the door. Still other designs comprised complicated mechanisms which could not be cost-effectively manufactured or had an unacceptable failure rate.